Finding the Third Proportional to 60,709.50 and 128,815.50

Step by Step Solution

1. Step 1: Write the proportion equation
   60,709.50 : 128,815.50 = 128,815.50 : x
2. Step 2: Convert to fraction form
   60,709.50/128,815.50 = 128,815.50/x
3. Step 3: Cross multiply
   60,709.50x = 128,815.50 × 128,815.50
4. Step 4: Simplify right side
   60,709.50x = 16,593,433,040.25
5. Step 5: Solve for x
   x = 16,593,433,040.25/60,709.50
6. Step 6: Final answer
   x = 273,325.15